when the case assortment list for 13 Wishes came out, it looked as though Lagoona was going to be the hardest to find as she was to be 1 in 6 in wave 1 and not in wave 2 at all, and Twyla would be the easiest since she got 3 of the 6 slots in the first wave, and 2 of 6 in the second wave.
this has not been my experience at all. since i started my weekly walmart runs a few weeks ago, I have seen Lagoona every time, but today is the first time i've seen Twyla. there were 3 of her out, so they must have just opened a fresh wave 1 case.
i'm not really sure why she's so scarce with her production numbers, but it looks like Mattel made a good call in uping her production.